Logstash Events

The Logstash Events stream connector allows you to send data from Centreon to Logstash. The stream connector translates Centreon data into a format that is understandable by Logstash, and sends it to an HTTP input plugin in Logstash.

• In most cases, you will want to send data from the central server. It is also possible to send it from a remote server or a poller (e.g. if you want to avoid the central server being a SPOF, or if you are an MSP and you install the stream connector on a poller or a remote server within your customer's infrastructure).
• By default, the Logstash Metrics stream connector sends host_status and service_status Broker events. The event format is shown here.
• These events are sent each time a host or a service is checked. Various parameters let you filter out events.

Installation

Perform the installation on the server that will send data to Logstash (central server, remote server, poller).

1. Login as root on the Centreon central server using your favorite SSH client.

2. Run the following command:

Alma / RHEL / Oracle Linux 8

dnf install centreon-stream-connector-logstash

Alma / RHEL / Oracle Linux 9

dnf install centreon-stream-connector-logstash

Debian_11

apt install centreon-stream-connector-logstash

Configuring your Logstash equipment

You may need to configure your Logstash equipment so that it can receive data from Centreon. Please refer to Logstash's documentation. Make sure Logstash is able to receive data sent by Centreon: flows must not be blocked by Logstash's configuration or by a security equipment.

Configuring the stream connector in Centreon

1. On your central server, go to Configuration > Pollers > Broker configuration.
2. Click on central-broker-master (or the appropriate broker configuration if it is a poller or a remote server that will send events).
3. On the Output tab, select Generic - Stream connector from the list and then click Add. A new output appears in the list.
4. Fill in the fields as follows:

Field	Value
Name	Logstash events
Path	/usr/share/centreon-broker/lua/logstash-events-apiv2.lua
Filter category	Neb

5. To enable Centreon to connect to your Logstash equipment, fill in the following mandatory parameters. The fields for the first entry are already present. Click on the +Add a new entry link located below the Filter category table to add another one.

Type	Name	Value explanation	Value exemple
string	http_server_url	the url of the logstash http plugin	https:/mylogstash.test
number	port	the port of your logstash http plugin	8443

6. Fill in any optional parameters you want (using the +Add a new entry link):

Type	Name	Value explanation	default value
string	username	the username if your are using https with basic auth for your logstash http plugin
string	password	the password of your user if you are using https with basic auth for your logstash http plugin
string	logfile	the file in which logs are written	/var/log/centreon-broker/logstash-events.log
number	log_level	logging level from 1 (errors) to 3 (debug)	1

7. Use the stream connector's optional parameters to filter or adapt the data you want Centreon to send to Logstash.

8. Deploy the configuration.

9. Restart centengine on all pollers:

   systemctl restart centengine

   Logstash should now receive data from Centreon. To test if it is working, see Curl commands: testing the stream connector.

Filtering or adapting the data you want to send to Logstash

All stream connectors have a set of optional parameters, that allow you to filter the data you will send to your Logstash equipment, to reformat the data, to define a proxy...

Each optional parameter has a default value, that is indicated in the corresponding documentation.

• To override the default value of a parameter, click on the +Add a new entry link located below the Filter category table to add a custom parameter. For example, if you want to only send to Logstash the events handled by a poller named "poller-1", enter:

  type = string
  name = accepted_pollers
  value = poller-1

• For the Logstash Events stream connector, the following values always override the default values, you do not need to define them in the interface.

Type	Name	Default value for the stream connector
string	accepted_categories	neb
string	accepted_elements	host_status,service_status

Event bulking

This stream connector is compatible with event bulking. Meaning that it is able to send more that one event in each call to the Logstash HTTP plugin.

To use this feature you must add the following parameter in your stream connector configuration.

Type	Name	Value
number	max_buffer_size	more than one

Event format

This stream connector will send event with the following format.

service_status event

{
  "event_timestamp": 1653434348,
  "hostname": "my-host",
  "output": "[CRITICAL] low power",
  "service": "my-service",
  "state": "CRITICAL",
  "title": "CRITICAL: my-host, my-service"
}

host_status event

{
  "event_timestamp": 1653434348,
  "hostname": "my-host",
  "output": "[DOWN] server is down",
  "state": "DOWN",
  "title": "DOWN: my-host"
}

Custom event format

This stream connector allows you to change the format of the event to suit your needs. Only the event part of the json is customizable. It also allows you to handle event types that are not handled by default such as ba_status events.

In order to use this feature you need to configure a json event format file and add a new stream connector parameter.

Type	Name	Value
string	format_file	/etc/centreon-broker/logstash-events-format.json

The event format configuration file must be readable by the centreon-broker user.

To learn more about custom event formats and templating files, read this documentation.

Curl commands: testing the stream connector

Sending events

If you want to test that events are sent to Logstash correctly:

1. Log in to the server that you configured to send events to Logstash (your central server, a remote server or a poller).

2. Run the following command:

curl -X PUT -H "accept: application/json" curl -X PUT 'http://<logstash_address>:<logstash_port>' -d '{"event_timestamp": 1653434348,"hostname": "my-host","output": "[DOWN] server is down","state": "DOWN","title": "DOWN: my-host"}'

Replace all the <xxxx> inside the above command with their appropriate value. <logstash_port> may become 8080.

3. Check that the data has been received by Logstash.